The invention relates generally to biocidal compositions and methods of their use for the control of microorganisms in aqueous and water-containing systems. The compositions comprise a hydroxymethyl-substituted phosphorus compound and an isothiazolinone compound selected from 1,2-benzisothiazolin-3-one, 2-methyl-1,2-benzisothiazolin-3-one, and mixtures thereof.
Protecting water-containing systems from microbial contamination is critical to the success of many industrial processes, including oil or natural gas production operations. In oil and gas operations, microorganism contamination from both aerobic and anaerobic bacteria can cause serious problems such as reservoir souring (mainly caused by anaerobic sulfate-reducing bacteria (SRB)), microbiologically influenced corrosion (MIC) on metal surfaces of equipment and pipelines, and degradation of polymer additives.
Biocides are commonly used to control the growth of microorganisms in aqueous and water containing systems. However, not all biocides are effective against a wide range of microorganisms, particularly when used at low concentrations. In addition, some biocides do not provide microbial control over long enough time periods, or alternatively are effective over long time periods, but not short time periods.
While some of these shortcomings can be overcome through use of larger amounts of the biocide, this option creates its own problems, including increased cost, increased waste, and increased likelihood that the biocide will interfere with the desirable properties of the treated medium. In addition, even with use of larger amounts of the biocide, many commercial biocidal compounds cannot provide both short term and long term effectiveness.
The problem addressed by this invention is the provision of biocides that are effective against a wide range of microorganisms, that may be used in reduced amounts so as to be economically and environmentally attractive, and/or that are effective for both short term and long term control of microorganisms.